The present invention relates to a bolt for use with an external fixator system which simplifies the fixation of a wire to the frame of the external fixator.
Currently, there are many bone deformities or fractures that external fixators can correct. Such fixators are known, for example, as Ilizarov apparatus.
Usually such an external fixator comprises rings also designated as fixation plates connected by threaded rods or struts to manipulate angulations, translation and length discrepancies of bones. Furthermore the fixation plates are in connection with bony structure by means of wires or pins which usually extend through the rings. The wires or pins are in connection with the plates by means of bolts and nuts. Furthermore the wires have to be tensioned before a fixed connection will be established by means of the bolts and the nuts which leads to a very complicated procedure for the surgeon as several tools have to be used.
First of all the wire has to be fixed by means of a bolt and a nut on one end. Thereby a first wrench has to be used to tighten and a second wrench has to be used to provide a counter torque against the tightening torque.
Afterwards the wire has to be tensioned by means of a wire tensioner and to be secured on the other end. In order to secure the wire two wrenches also have to be used. This means that three tools are used to fix the wire at the second end, namely the wire tensioner and the two wrenches. This is very cumbersome for the surgeon as at least one further person is needed to fix the wire and also the limited space situation leads to difficulties.
Such a prior art system is shown by FIG. 1 from it can be seen that three different tools are used to tighten and to fix the wire to the ring or plate of an external fixator. Thereby a wire tensioner has to be used to tension the wire. The wire tensioner here is designated with reference numeral 5. Furthermore two wrenches have to be used to tighten the bolt and the nut. This means that at least two persons are necessary to tension and to fix the wire. Usually one person manipulates the wire tensioner, whereas the other person handles the wrenches.
A further problem arises when the bolts and nuts have to be re-tightened afterwards it is very likely that there is slight rotation of the opening within the bolt through which the wire extends and therefore the wire looses its alignment.